Chemical warfare agents have sometimes been defined as including poison gases, incendiary materials, and biological microorganisms employed to disable personnel, as well as pesticides, herbicides, and similar substances which can be employed to interfere with the growth of plants, insects, and other non-mammalian species; in this regard, see the definition "chemical warfare" which appears in the "Concise Encyclopedia of Science & Technology," Second Ed., McGraw-Hill Book Co., New York, N.Y. (USA), 1989.
As employed herein, the term "chemical warfare agent," which is sometimes abbreviated as "CWA", is intended to include only those agents which are effective in relatively small dosages to substantially disable or kill mammals. Thus, the definition excludes substances which are agricultural chemicals used primarily to control plants, Hexapoda, Arachnida, and certain fungi. Furthermore, for purposes of this invention, the term "chemical warfare agent" also excludes those replicating microorganisms commonly known as biological warfare agents, including viruses, such as equine encephalomyelitis; bacteria, such as those which cause plague, anthrax and tularemia; and fungi, such as coccidioidomycosis; as well as toxic products expressed by such microorganisms; for example, the botulism toxin expressed by the common Clostridium botulinium bacterium.
Also excluded from the term "chemical warfare agent," as it is used herein, are those naturally occurring poisons, such as capisin (an extract of cayenne pepper and paprika), ricin (a toxic substance found in the castor bean), saxitoxin (a toxic substance secreted by certain shellfish), cyanide salts, strychnine (a plant-derived alkaloid), and the like. In addition, the term "chemical warfare agent" is not intended to encompass incendiaries such as napalm or explosives such as gunpowder, TNT, nuclear devices, and so forth.
On the other hand, a series of "poison gases" appeared on battlefields in the World War I era. These substances are primarily gases near room temperature and include cyanogen chloride, hydrogen cyanide, phosgene and chlorine. These poisonous gases are included within the definition of the term "chemical warfare agent" as used herein. That term is also intended to encompass those primarily liquid substances, including vesicants which were first used in World War I, and refinements, such as the nerve agents, which have appeared on the scene more recently.
The term "chemical warfare agent" in this application includes substantially pure chemical compounds, but the term also contemplates mixtures of the aforesaid agents in any proportions, as well as those agents in impure states in which the other components in the mixture are not simply other CWA's. "Chemical warfare agents," as used herein, also includes partially or completely degraded CWA's, e.g., the gelled, polymerized, or otherwise partially or totally decomposed chemical warfare agents commonly found to be present in old munitions.
In January 1993, representatives from more than 130 nations signed the final draft of the Chemical Weapons Convention, which outlaws the production, use, sale, and stockpiling of all chemical weapons and their means of delivery and calls for the destruction of existing stocks by the year 2005. About sixty of the signatory nations have ratified the treaty. In 1993, some 20 nations were suspected of possessing chemical arsenals or having the means to make them.
An estimated 25,000 tons of CWA's in the United States and 50,000 tons of CWA's in the former Soviet Union, contained in bulk storage vessels, metal barrels, canisters, rockets, land mines, mortar and artillery shells, cartridges, and missiles, must be destroyed if the 1993 Convention is to be carried out. The costs for carrying out this destruction have been estimated at US$ 8 billion and US$ 10 billion, respectively, for the United States and the former Soviet Union alone.
Over the years a number of studies have designated incineration as the preferred method of destruction for CWA's because of the perceived low cost and relative simplicity of incineration technology. However, it is becoming clear that incineration of chemical warfare agents poses risks of both an immediate and long term nature which may not be acceptable to the population. Public health and ecosystem integrity are threatened by the emission of materials which can escape the combustion train, resulting in uncharacterized products of incomplete combustion becoming dispersed into the atmosphere.
Less than 72 hours after start-up, the U.S. Army had to shut down its first domestic CWA destruction facility in Tooele, Utah, located in a sparsely populated region in the western United States, when the nerve agent Sarin was detected in an area outside the chamber in which Sarin-filled rockets were being destroyed. It is unclear if or when the facility will resume its activities.
Earlier public opposition to incineration had forced U.S. government authorities to consider alternative methods, including chemical treatment of the CWA's, capable of leading to environmentally neutral products. However, this concept was dismissed in the United States after publication in 1984 of a National Research Council report stating that, when compared to incineration, chemical neutralization processes "are slow, complicated, produce excessive quantities of waste that cannot be certified to be free of agent, and would require higher capital and operating cost."
Alternatives to incineration are cited, for example, in the table of contents from the "Proceedings, Workshop on Advances in Alternative Demilitarization Technologies," held in Reston, Va. USA on Sep. 25-27, 1995. Technical papers presented relate to molten salt oxidation, supercritical water oxidation, electrochemical oxidation, neutralization, hydrolysis, biodegradation, steam-reforming, and so forth.
The chemical treatments proposed in the past for destroying chemical warfare agents were not entirely satisfactory. For example, the treatments were not universally applicable. It should be recognized that most chemical reagents are species-specific; that is, a chemical reagent generally reacts with a substance having a certain specific functional group. An acid reacts with a base, much less commonly with another acid. An oxidizing agent reacts with an oxidizable substance, such as a reducing agent. With such species-specific chemistry, destruction of a CWA would require one to first establish the identity of the CWA or the mixture of CWA's to be destroyed in order to select the right reagent or combination of reagents to react with that particular material.
Operationally, chemical processing, as envisioned in the past, would frequently require handling and transferring of CWA's by human operators. Such handling operations could include, for example, removal of the CWA from a warhead or missile casing, canister or other containerized delivery system, thereby exposing personnel to the grave danger of contact with the CWA. Loading the CWA so-removed from its container into a separate reaction vessel would lead to another opportunity for exposure to the CWA.
Finally, chemical methods previously proposed for the destruction of chemical warfare agents were believed to have unacceptable capital requirements for equipment, facilities, and personnel safeguards, as well as requiring time-consuming, labor-intensive processing. Then, there was also envisioned the further cost of disposing of the products after the CWA destruction chemistry had been carried out. In light of all this, one can understand why, compared against such chemical treatments, incineration of the CWA's, producing water, carbon dioxide and inorganic salts (ideally), seemed attractive indeed. However, incineration is turning out to be less than the anticipated panacea.